Approximately 15 percent of pregnancies end between week four and week 20 in miscarriage, also known as spontaneous abortion. Spontaneous abortion means the pregnancy ends due to natural causes, versus surgical or medical. Recurrent miscarriage is defined as three or more consecutive spontaneous abortions. Recurrent miscarriage in fertility patients is especially tragic because they have often undergone months of fertility treatment to achieve pregnancy.
UAB reproductive specialists have years of experience managing women who suffer from recurrent miscarriage and infertility. Their combined experience is unparalleled in the region, and you can be assured of a complete evaluation of your condition to determine the most current and effective treatments to best serve you.
The most common causes of recurrent miscarriage are genetic abnormalities, uterine structural deformities, and endocrine diseases. The incidence of spontaneous abortion increases as women age, which is most likely due to chromosome abnormalities. It is also higher in women with polycystic ovarian syndrome.
Genetic abnormalities are the most common cause of miscarriage, usually occurring as a random event. In most cases, genetic abnormalities are not seen in the parents. In the fetus, the most common genetic cause is aneuploidy, or an abnormal number of a particular chromosome (for example, 3 chromosomes instead of 2). In particular, chromosomes 13, 16, 18, and 21 are common for aneuploidy. A fetus may also have only 1 copy instead of 2 of a particular chromosome, which can cause pregnancy loss.
If the couple does have a known genetic disease that could be transferred to their child, preimplantation genetic diagnosis (PGD) can be used to screen for certain genetic diseases such as hemophilia, Tay- Sachs, and many others. The couple undergoes an In Vitro Fertilization cycle, and the resulting embryos are biopsied to learn if they carry the disease. This process is especially useful in couples who have “sex-linked” diseases. Even though PGD is an extremely useful diagnostic/screening tool, it does not replace an amniocentesis, a test in which amniotic fluid is analyzed, during pregnancy.
Uterine abnormalities—or malformations—include the septate uterus in which the uterus is divided by a septum, Asherman’s syndrome in which scar tissue develops in the uterus, large polyps or fibroids, and uterine scarring from infection. With today’s surgical techniques, many of these conditions can be corrected by a reproductive surgeon. However, conditions such as a unicornuate uterus cannot be surgically treated. When structural damage is severe, the only option for couples desiring a genetically related child is to use a surrogate mother.
Endocrine, or hormonal, disorders are also a cause of recurrent miscarriage. Polycystic ovarian syndrome is associated with elevated levels of luteinizing hormone and testosterone, which are linked to miscarriage. Type 1 diabetes and untreated thyroid disease are other potential endocrine causes of recurrent miscarriage.
Antiphospholipid antibody syndrome is a well characterized cause of spontaneous abortion. In this syndrome the body mistakes phospholipids (a component of the cell membrane) as an antigen (invading pathogen or allergen) and produces antibodies to destroy them. Lupus anticoagulant and/or high anticardiolipin antibodies have been associated with first, second, and third trimester spontaneous abortions. It is thought that the antibodies cause small clots in the vessels of the placenta, restricting blood flow to the fetus, causing poor fetal growth, high blood pressure in the mother, and stillbirth.